For many years, petroleum has been recovered from subterranean reservoirs through the use of drilled wells and production equipment. During the production of desirable hydrocarbons, such as crude oil and natural gas, a number of other naturally occurring substances may also be encountered within the subterranean environment.
The removal of unwanted deposits from the wellbore and production equipment is generally referred to as “remediation.” In contrast, the term “stimulation” generally refers to the treatment of geological formations to improve the recovery of hydrocarbons. Common stimulation techniques include well fracturing and acidizing operations. Well remediation and stimulation are important services that are offered through a variety of techniques by a large number of companies.
Oil and natural gas are found in, and produced from, porous and permeable subterranean formations. The porosity and permeability of the formation determine its ability to store hydrocarbons, and the facility with which the hydrocarbons can be extracted from the formation.
The use of certain microemulsion additives during completion of both oil and gas wells leads to higher near wellbore permeability and long-term increased production of hydrocarbons from the well. The increased displacement of water from the formation and proppant by both oil and gas (flowback) and consequent increased production of hydrocarbons have been attributed to lowered capillary pressure. However, the solvent—hydrocarbon surfactant systems that have been used have limitations in their ability to lower capillary pressure. There is, therefore, a need for treatment compositions that are capable of lowering capillary pressure and increasing wettability while maintaining the desirable properties of conventional emulsified treatment formulations.